Implantation of an electrode in a left-ventricular vein via the coronary sinus is currently considered to be a state-of-the-art procedure for left-ventricular stimulation and detection. These so-called coronary sinus electrodes are used primarily for cardiac resynchronization therapy.
The medical literature contains a growing number of case reports of transseptal implantation of left-ventricular stimulation electrodes for resynchronization therapy. These implantation techniques have always been implemented with the help of existing catheters, guide wires and electrodes. Puncture of either the atrial septum or the ventricular septum has been described for access to the left ventricle. See, for example, Transseptal Endocardial Left-Ventricular Pacing: An Alternative Technique for Coronary Sinus Lead Placement in Cardiac Resynchronization Therapy, B. M. van Gelder, M. G. Scheffer, A. Meijer, et al., Heart Rhythm April 2007: 4(4):454-60.
Furthermore, concepts for transmural left-ventricular pressure measurement are also currently being investigated in clinical trials wherein pressure sensors are placed transmurally in the left ventricle for permanent telemetric pressure monitoring in the left ventricle. See, e.g., www.transomamedical.com or the following technical publications:    A Novel Technique for Assessing Load-Dependent Cardiac Function During LVAD Support Using Telemetered Left-Ventricular Pressure. P. 1. McConnell, C. L. Del Rio, P. Kwiatkowski, D. Farrar, T. Shipkowitz, R. E. Michier, B. Sun, ASAIO Journal 51(2): 31A, March/April 2005;    In-Vivo Safety and Accuracy of a Clinically Applicable Telemetered Left-Ventricular Pressure Module: Intermediate-Term Results, P. I. McConnell, D. de Cunha, T. Shipkowitz, J. Van Hee, P. Long and R. Hamlin, Heart Failure Society Meeting, September 2004;    A System for Long-Term Measurement of Left-Ventricular Pressure in Heart Failure Patients Living at Home, N. Sweitzer, S. Park, Heart Failure Society Meeting, September 2002;    Automated Non-Invasive Monitoring of Left-Ventricular Hemodynamics During Onset of Heart Failure in an Ambulatory Yucatan Mini Pig Model Using a New System Under Development for Assessing Heart Failure Patients at Home, S. Park, N. Sweitzer, Heart Failure Society Meeting, September 2002; or    A System for Long-Term Measurement of Left-Ventricular Pressure in Heart Failure Patients Living at Home, S. Park, N. Sweitzer and G. May, Heart Failure & Circulatory Support Summit, Cleveland, Ohio, August 2002.
A number of commercial closure systems are currently available for congenital atrial septal defects, open foramen or foramen ovale and ventricular septum defects (e.g., Premere™ PFO, SJM), which can be positioned via catheter techniques and which ensure a reliable closure of the septum defect. In this regard, see Transcatheter Patent Foramen Ovale Closure Using the Premere PFO Occlusion System, Andrea Donti, Alessandro Giardini, Luisa Salomone, Roberto Formigari, Fernando M. Picchio, Catheterization and Cardiovascular Interventions, vol. 68/5 2006.
WO 2006/105395 A2 describes a transseptal/transmyocardial ventricular stimulation electrode.
In approximately 10-15% of the implantations, anatomical conditions prohibit reliable implantation of a left-ventricular coronary sinus electrode. Furthermore, the incidence of dislocation of left-ventricular electrodes implanted for cardiac resynchronization therapy (CRT) by way of the coronary sinus is greater than that with a traditional right-ventricular pacemaker electrode. For these reasons, purely left-ventricular stimulation using a coronary sinus electrode is not currently being used for treatment of bradycardia or for implantation of automatic cardioverter/defibrillators (ICD), because neither the success nor the safety of implantation is guaranteed with this type of left-ventricular electrode. The very limited options for placement are another disadvantage of a coronary sinus electrode. In most cases, there are only one or two different positions for attachment of the probe. This is discussed as one of the primary causes of the poor responder rate (60-70%) of CRT at the present time.
The techniques presented above for electrode implantation in the left ventricle via the atrial or ventricular septum are very complex and have not yet been successful because of the risks (RV shunt, thrombi). Free placement of the electrode in the left ventricle is possible here, and this would eliminate the disadvantages of attachment of the probe, the responder rate, and anatomical restrictions.
Transluminal LV pressure measurement can be used for a system to permanently penetrate through the myocardium into the left ventricle. This introduces a very short probe into the left ventricle which has a pressure sensor and is of the type that cannot be used for electric stimulation of the heart. However, the probe described in WO 2006/105395 A2 is designed so that the active stimulation area lies only in the area of the left-ventricular septum and cannot be positioned freely in the left ventricle. In addition, WO 2006/105395 A2 does not discuss repositioning or the explantation ability of an electrode.